Control pests at your outdoor events with the Air Core Technology Skeeterlog® 100% Natural Insect Repellent! The Air Core Technology Skeeterlog supports optimal intentional use for the Steel Chimney. The air core rests on the steel pin in the center of the Steel Chimney. The plum rises straight above the core through the center of the top of the Steel Chimney. A consistent plum of smoke bearing the secret Skeeterlog formula rises steadily from the Air Core Skeeterlog used in the Steel Chimney.